It's called "Set Object Volume". Just drag and drop the rvb file over a viewport in Rhino and run the command "SetVolume". Then follow the command line instructions to scale multiple objects in unison while targeting a specific volume for one of them.

About McNeel

Founded in 1980, McNeel is a privately-held, employee-owned company with sales and support offices and affiliates in Seattle, Boston, Miami, Buenos Aires, Barcelona, Rome, Tokyo, Taipei, Seoul, Kuala Lumpur, and Shanghai with more than 700 resellers, distributors, OEMs, and training centers around the world.